1. Field of the Invention
This invention relates to a chemical analysis element cartridge for storing a plurality of chemical analysis elements, such as those for quantitatively analyzing the content of a specific chemical, biochemical or immunochemical component contained in a sample liquid such as blood or urine and for measuring the concentration (activity) of particular ionic substances in a sample liquid such as blood or urine, and taking out the same one by one.
2. Description of the Prior Art
There has been put into practice various "dry-to-the-touch" chemical analysis elements.
For example, there has been proposed, for instance, in U.S. Pat. Nos. 3,992,158; 4,292,272 and 5,019,347 and European Patent 0 162 302B, and put into practice a "dry-to-the-touch" chemical analysis film with which the content of a specific chemical, biochemical or immunochemical component contained in a sample liquid (hereinafter referred to as an analyte), the activity thereof or the content of a solid component can be quantitatively analyzed by only spotting a droplet of the sample liquid on the film. As such a dry chemical analysis film, there has been known an integrated multi-layered chemical analysis film (sometimes referred to as "multi-layered chemical analysis element") comprising a support sheet of organic polymer and at least one reagent layer which contains a reagent and is formed on the support sheet. A spreading layer is preferably provided over the reagent layer. Further a dry chemical analysis element which is formed of filter paper and has one or more layers has been proposed, for instance, in U.S. Pat. No. 4,477,575, and partly put into practice.
When quantitatively analyzing the chemical, biochemical or immunochemical components or the like contained in a sample liquid using such a dry chemical analysis film, a droplet of the sample liquid is spotted on the film (on the spreading layer when the film is provided with a spreading layer and directly on the reagent layer when the film is not provided with a spreading layer) and is held at a constant temperature for a predetermined time (incubation) in an incubator so that coloring reaction occurs, and the optical density of the color formed by the coloring reaction is optically measured. That is, measuring light containing a wavelength which is pre-selected according to the combination of the component to be analyzed and the reagent contained in the reagent layer of the film is projected onto the film and the optical density of the film is measured. Then the concentration or the activity of the component to be analyzed is determined on the basis of the optical density using a calibration curve which represents the relation between the concentration of the chemical, biochemical or immunochemical component and the optical density.
The integrated multi-layered chemical analysis film is generally in the form of a film chip of a predetermined shape such as square or rectangle. The film chip is sometimes provided with a frame of organic polymer for facilitating automated handling of the chemical analysis film and for flattening the film chip which is apt to be warped (curled or curved) into a roof tile-like shape in a dry state and is used in the form of a chemical analysis slide. In a biochemical analysis apparatus we have proposed previously, the film chip is used as it is without frame (will be referred to as "frameless chemical analysis film", hereinbelow). A plurality of the frameless chemical analysis films are loaded in a cartridge and the cartridge is loaded in a chemical analysis film supplier for a biochemical analysis apparatus. The frameless chemical analysis films are taken out from the cartridge in the supplier one by one.
Use of the frameless chemical analysis film is advantageous over use of the chemical analysis slides in the following point. That is, the chemical analysis slide is larger than the frameless chemical analysis film by the size of the frame and accordingly parts of the biochemical analysis apparatus must be larger, which obstructs reduction in size of the biochemical analysis apparatus and at the same time results in reduction of the overall throughput capacity of the biochemical analysis apparatus. Thus the use of the chemical analysis slides adds to the cost of measurement.
Further there has been proposed, for instance, in U.S. Pat. Nos. 4,053,381 and 4,437,970 and put into practice a "dry-to-the-touch" electrolyte analysis slide for quantitatively analyzing the activity of particular ionic substances contained in a sample liquid such as blood or urine in a potentiometric way. The electrolyte analysis slide is a kind of electrochemical sensors and comprises an ion selective electrode pair.
In this specification, the term "chemical analysis element" should be broadly interpreted to include the chemical analysis slide, the frameless multilayered chemical analysis film, the single-layered or multi-layered chemical analysis element formed of filter paper (with or without frame), and the electrolyte analysis slide described above.
For instance, in Japanese Patent Publication 57(1982)-53271 and U.S. Pat. No. 4,151,931, there is disclosed a chemical analysis element cartridge in which a plurality of chemical analysis elements are stacked and from which the chemical analysis elements are taken out one by one. In the cartridge, a plurality of chemical analysis elements are stacked in a cartridge which is provided with an element take-out port in a side surface of the upper portion of the cartridge, and the uppermost element is pushed out and fed to an analysis apparatus through the element take-out port by a pusher blade which is moved in a horizontal direction. The stack of the elements are supported on a support member which is disposed in the cartridge and is permitted to move only upward by a ratchet mechanism, and the support member is lifted upward by a plunger inserted into the cartridge from below so that the stack of the elements is moved upward by a distance equal to the thickness of one element and the second uppermost element is brought to the element take-out port each time the uppermost element is pushed out.
However this cartridge is disadvantageous in the following points. That is, since the plunger is inserted into the cartridge through an opening formed in the bottom of the cartridge to push upward the support member, thereby urging the stack of the elements toward the take-out port, the stroke of the plunger is long and a long time is required for operation of the plunger. Accordingly when a plurality of elements are taken out from a plurality of cartridges for different analytes, take-out efficiency is low, which makes difficult mass-handling by shortening of the handling time.
Further in order to insert and retract the plunger into and from the cartridge in the vertical direction, a height equal to the sum of the height of the cartridge, the length of the plunger and the stroke of the plunger is required, which adds to the size of the apparatus.
Further in the cartridge described above, the support member is prevented from moving in the reverse direction by the ratchet mechanism. This involves the following problem in the case where the frameless chemical analysis films are stored in the cartridge. That is, the frameless chemical analysis films, which are curled in the dry state as described above, are compressed between the support member and the end wall of the cartridge adjacent to the element take-out port and flattened when urged toward the element take-out port, whereby restoring resilient force is produced and as a result, a larger pressing force acts on the frameless chemical analysis films.
In the case of the frameless chemical analysis films, it is difficult to push out each film from the cartridge by use of a pusher blade such as described above since the films are curled and the state of curl differs from film to film. For example, the films can be taken out by attracting them under a suction force by a suction pad. However since the attracting force under a suction force is limited, it is difficult to surely take out the films when the films are pressed toward the element take-out port under a large pressing force.
Further in the stack of the frameless chemical analysis films, the spreading layer of each film is in a direct contact with the adjacent film and accordingly when the film is pulled out while the films are pressed under a large pressing force, the spreading layer can be rubbed and damaged to such an extent that a desired spreading performance cannot be obtained.